Many users rely on cellular networks for entertainment, social activities and business critical tasks, such as stock trading, navigation, and emergency services. The phenomenal traffic growth and vast diversity in both applications and mobile devices pose significant challenges to cellular service providers. The cellular networks are extremely complex and constantly evolving at a rapid pace. Changes are introduced to either support new service features (e.g., hardware and software changes), such as voice over LTE, LTE-advanced, small cells, and software patches (e.g., for bugs), among other things. Deploying changes in a cellular network are usually done with extreme caution in order to avoid any unexpected performance degradation or failures. Extensive testing is typically conducted in large-scale laboratory settings, but it is extremely difficulty to replicate the large-scale, diverse variations and extreme complexity of real operational networks. Thus, the changes are tested on a smaller scale in the field. This small scale testing in the field is referred to as the First Field Application (FFA).
A goal of FFA testing is to identify and infer the performance impacts of the change and make a recommendation for a go/no-go decision for a network-wide roll-out. If the desirable service performance impacts (e.g., improvements or at times no change in performance) are observed after the FFA, the decision is to go-ahead with the roll-out. However, if performance degradations are observed, the changes need to be rolled back at the FFA locations and further analysis need to be conducted in lab settings.
The performance impact during FFA is carefully analyzed by the network operation and engineering teams. Once they certify the change using field test results, the network-wide roll-out begins at a rapid pace. Strict deadlines are set to quickly update the network. Any unexpected issues discovered in the network-wide roll-out would slow down the process because of the need to understand the negative performance impact during FFA. This can occasionally happen because of the large scale network, diversity of network equipment, complex topology, multiple technologies, transport architectures, and dependency of service performance on external uncontrollable factors. Thus, careful planning and design of field tests is important to ensure smooth roll-out for the network-wide deployment.
Cellular networks are constantly evolving due to frequent changes in radio access and end user equipment technologies, dynamic applications and associated traffic mixes. Network upgrades should be performed with extreme caution since millions of users heavily depend on the cellular networks for a wide range of day to day tasks, including emergency and alert notifications. Before upgrading the entire network, field evaluation of upgrades may be conducted. Field evaluations are typically cumbersome and can be time consuming; however if done correctly can help alleviate many of the deployment issues that are associated with service quality degradation.